When disease is suspected in a living being, the physician must arrive at a specific diagnosis. Some disease processes, particularly tumors, require a histologic and/or cytologic diagnosis. While radiologic tools are useful in detecting the presence of a tumor, the cell type of the tumor can only be determined by a pathologist's examination of a histologic or cytologic sample of the tumor. There are a number of devices that have been fashioned to actually perform the act of taking tissue samples. These devices may obtain tissue for histology or in the case of needle aspiration biopsies, samples for cytology and histology. In many cases, these samples are very small and difficult to retrieve and process. These small tissue fragments may originate from a punch, or similar biopsy procedure devices or from Fine Needle Aspiration Biopsy (FNAB) biopsies. FNAB is typical and produces single cells, small cell clumps and fragments which are immediately smeared onto a glass slide (direct smears) or rinsed into a container with preservative fluid. After being transported to the laboratory, these samples are centrifuged onto a glass slide (cytospin smears). In some cases needle aspiration biopsy produces tissue fragments which are large enough to process histologically. If successfully retrieved, these fragments are submitted in blood clot or agar in a technique known as cell block preparation which are then immobilized in wax for sectioning and slide preparation.
FNAB is one example of the tissue collection techniques used and the problems which are of interest to the present invention. Fine Needle Aspiration Biopsy techniques have been practiced for many years and the literature contains many studies on technique and comparison of various improved devices for same. There exists two different kinds of biopsy needles. Those with active or movable cutting elements and those that are passive or non-moving. Active needles have two basic problems, which are cost and complexity. The needles that are of interest to this invention are most often 22 gauge which is 0.028″ OD with a standard wall of 0.006″. This leaves only 0.016″ ID. Some prior art designs use an active element down the ID bore to sever and capture tissue. 0.016″ does not provide a great deal of clearance for these elements and thus these prior art needles are inefficient. If it is desired to further suck tissue fragments up the needle bore further reducing the bore, the bore will be further reduced because a second element must be added, which is counter productive.
Other methods of obtaining samples are also discussed in the literature and also have problems. Each is characterized by tissue size and number of pieces generally available as well as whether orientation in the eventual sectioning plane is critical for example:
Fine Needle Aspiration Biopsy—very small pieces of tissue taken from the core of a fine needle; usually transported in fixative solution;
GI biopsy—characterized by a few small tissue pieces; it is desirable to concentrate the tissue pieces in close proximity to each other;
Prostate chips—orientation is irrelevant for these samples;
Endometrial Curettings—characterized by varying size samples; orientation is irrelevant;
Vessel—orientation is critical; sections need to be transverse;
Core Biopsy—i.e. from the prostate—orientation is critical; the tissue should lie flat all in the same plane;
Gall bladder—orientation is critical—the tissue should be embedded on edge;
Uterine Wall, breast or large tumors—orientation is not critical—sample lies flat in a plane.
Some of these methods are characterized by the possibility of supplying extremely small tissue samples. Some samples can be as small as a few cells, and extremely small samples can create problems. These problems include loss of the sample, dehydration of the sample, and contamination of the sample during harvesting, storage and transport. Still further, as will be more evident from the following discussion, small samples are extremely difficult and time consuming to process in the laboratory.
Still further, in many cases, a tissue sample is mixed with effluent. Prior art devices and methods account for collection of effluent only and do not provide devices and methods for trapping tissue specimens. The prior art collects effluent, but does not provide devices or methods for the separation of tissue from the effluent. Therefore, there is a need for apparatus and a method for handling effluent as well as tissue samples and for efficiently separating tissue from effluent.
Once a tissue sample is harvested it must be transported to the pathology lab for processing. Currently, handling and processing of small biopsies in the histology laboratory is a tedious task and requires multiple manual manipulations of the specimen. Fine Needle Aspiration Biopsy (FNAB) is typical. Therefore, there is a need to handle and process very small samples of tissue in an expeditious manner.
In addition to the above problems, a further problem with currently used apparatus and methods is associated with the orientation of samples. Currently, in a pathology lab, the pathologist will gross-in the tissue samples, cut them into appropriate size specimens, if necessary, and place them into a tissue cassette for processing. Herein lies one of the biggest problems of the existing art. When the tissue sample is placed into the tissue cassette, the pathologist orients the sample so that any surface in which he or she desires to see sectioned is placed face up in the cassette. The histotech who retrieves the tissue from the cassette after processing knows through training that when opening the cassette the tissue surface that faces up when first opened is then placed face down into the wax mold, which in turn will become the first surface to be sectioned by a microtome blade. This is an established protocol which is observed in most pathology labs today. This process then necessitates human involvement and redundant handling. In addition, sometimes special sponge materials must be packed into the cassette to keep a sample oriented or to prevent loss from the cassette if it is too small and may turn or lose its orientation during the tissue processing. Sometimes, notes and drawings accompany tissue samples to show how they should be oriented in the wax.
No current system or method provides the ability to maintain critical tissue orientation throughout these steps and eliminate human errors in the associated manual steps and procedures. Therefore, there is a need for a system and a process that can maintain the preferred orientation of the tissue sample from the time of initial gross-in throughout the tissue processing procedure and continuing through the wax embedding stage with no human involvement required beyond initial gross in.
Yet another problem associated with harvesting and handling of tissue samples for biopsy analysis is associated with the analysis process itself. In the analysis procedure, the sample is exposed to heat and chemicals which can cause the tissue and/or its support to change shape and/or move. The sample-holding structure should account for this or there may be a risk of damaging the sample or the sample holder. Accordingly, there is a need for an apparatus for holding a harvested biopsy sample in a manner that accommodates the tissue analysis process.
Another problem encountered with presently available systems is the lack of integration and multiple handling steps required to produce a sectioned sample for pathological examination. Therefore, there is a need for an approach which reduces the time and handling of biopsy samples.
By way of background, a review of the standard procedure that each sample must undergo to get from harvest to a prepared histologic slide is necessary. First, the sample must be taken with the appropriate instrument. The tissue is then retrieved from the instrument and deposited into some sort of specimen container, usually with a fixative such as 10% formalin. The container is labeled and transported to the pathology lab. Herein lies the first problem with the prior art. With no way to control where the sample lodges in the container, the sample may stick to the lid or sides of the container and become dried out before it reaches the pathology lab; rendering it difficult, if not impossible to interpret. In addition, the samples may be extremely small and may be hard to locate and retrieve from the container.
When the pathology laboratory receives the container, the specimen is logged into the manual or computerized anatomic pathology system and is assigned a unique surgical pathology accession number. This number is placed on the specimen container and is subsequently used to label histology slides, cassettes and the final surgical pathology report. The specimen is logged into the paperwork system and physically described in an appropriate medium, such as dictation or the like, by a pathologist or assistant. This is the description portion of the process known as “grossing-in” the specimen. The grossing in continues when the pathologist or assistant manually retrieves the specimen and views the specimen, and then sections the specimen into appropriate size morsels, if necessary, and places them into a plastic tissue cassette. If very tiny or multiple, the pieces of tissue must be immobilized within some device such as two layers of sponge or a tea bag to prevent them from escaping from the cassette during processing. Many times a surgeon will have taken diffuse biopsy samples or scrapings from the mucosal lining of an organ, such as an endocervical biopsy. Often these samples are very small and multiple such as is the case with tissue fragments from Fine Needle Aspiration Biopsy (FNAB). Other times a doctor will deposit the sample in filter paper which resembles a tea bag. All of these various tissue specimens end up in a tissue cassette. As used herein, the term “grossing-in” includes both the description of the tissue sample and the preparation of the tissue sample for further processing.
At the end of the day all of the cassettes are put into a tissue processor where the tissue is subjected to a sequence of solutions and heat. These solutions gradually replace water in the cells with alcohol, followed by xylene, and ultimately by wax. This gives the wax-impregnated tissue a similar consistency to the wax surrounding the tissue in the next step. After the tissue processing is complete, usually the following morning, the sample is again handled to remove it from the cassette where it is placed and oriented in a mold. At this point if a tea bag or sponge was used to immobilize the sample, the pathology lab is then faced with trying to extract or scrape the wax-impregnated specimen from the paper, before placing the specimen in the wax mold.
An embedding medium such as hot (molten) paraffin wax is poured into the mold to immobilize the tissue in a solid block of wax. Wax or parrifin can be used as an embedding medium; however, agar or even chemically setting resins such as polyester can be used. Harder resins can also be sectioned with a saw blade and then ground and polished to a thin film. After cooling, the wax block is removed from the mold, placed into a microtome and sectioned into thin slices approximately 4-6 microns thick. These sections are floated onto glass slides, stained, cover-slipped, and are then ready for microscopic examination. In this process, samples are handled or transferred many times. Each handling process takes time and human involvement.
Therefore, there is a need for apparatus and method to improve the harvesting of tissue samples. There is also a need for handling and processing those harvested tissue samples in an efficient and reliable manner that lends itself to automation and removes the need for a human to find, handle and orient a tissue sample before analysis of that sample can be performed.
Some long thin tissue samples are difficult to align and orient. The parent application discloses walls and pegs between which tissue is placed.
While in many instances those configurations work well, such as for fallopian tubes, in other instances, such as for gallbladder, it is difficult to place the tissue between the posts. Most often because the tissue sample varies in dimension from one end to the other. It is difficult to accommodate the many different sizes of tissue that are encountered in preparing biopsy samples. Therefore, there is a need for an orientation device which can be self accommodating to the differing dimensions of tissue samples. In addition, it is much easier to hold the tissue upright and place the orienting device over the tissue.
Once the tissue is properly supported by the orientation device, the device and the tissue are both subjected to the analysis process. Therefore, in addition to being easy to use in connection with biopsy samples, the orientation device must be able to withstand the analysis process and be sectionable as well.